Preventing cascade failures in computer systems

ABSTRACT

A computer hardware-implemented method, system, and/or computer program product prevents a cascading failure in a complex stream computer system causing an untrustworthy output from the complex stream computer system. Multiple upstream subcomponents in a complex stream computer system generate multiple outputs, which are used as inputs to a downstream subcomponent, wherein the multiple upstream subcomponents execute upstream computational processes. Each upstream computational process is examined to determine an accuracy of each identified output. An accuracy value is assigned to each of the multiple outputs from the upstream subcomponents, and weighting values are assigned to each of the inputs to the downstream subcomponent. If using the accuracy values and weighting values fails to adjust the downstream subcomponent to meet a predefined trustworthiness level for making a first type of prediction, then a new downstream computational process that produces a different second type of prediction is executed.

BACKGROUND

The present disclosure relates to the field of computers, andspecifically to the use of computers when used in cascading operations.Still more particularly, the present disclosure relates to theprevention of cascade failures in cascading operations in complex streamcomputer systems.

A complex stream computer utilizes software and hardware components thatinteract with one another, such that a downstream component is relianton an output from an upstream component in the complex stream computer.Such operations are known as cascading operations, since outputs ofupstream operations directly impact downstream operations. This impactcauses an upstream failure/fault/error to cascade through the complexstream computer, such that the actual internal cause for a final outputerror (i.e., a cascading failure in the stream computer) is difficult,if not impossible, to ascertain.

SUMMARY

A computer hardware-implemented method, system, and/or computer programproduct prevents a cascading failure in a complex stream computer systemcausing an untrustworthy output from the complex stream computer system.Computer hardware receives a first set of binary data that identifiesmultiple subcomponents in a complex stream computer system. Theidentified multiple subcomponents include multiple upstreamsubcomponents and a downstream subcomponent. The multiple upstreamsubcomponents execute upstream computational processes. The multipleupstream subcomponents reside within a first computer hardware system.The downstream subcomponent resides within a second computer hardwaresystem. The computer hardware receives a second set of binary data thatidentifies multiple outputs generated by the multiple upstreamsubcomponents. The computer hardware receives a third set of binary datathat identifies multiple inputs to the downstream subcomponent. Theidentified multiple inputs to the downstream subcomponent are theidentified multiple outputs generated by the multiple upstreamsubcomponents, and the identified multiple inputs are inputs to adownstream computational process that is executed by the downstreamsubcomponent. The computer hardware examines each of the upstreamcomputational processes to determine an accuracy of each of theidentified multiple outputs based upon a source of inputs to each of theupstream computational processes and a history of each of the upstreamcomputational processes for producing predictions that exceed apredetermined level of accuracy. The computer hardware generatesaccuracy values by assigning a determined accuracy value to each of theidentified multiple outputs. The determined accuracy value describes aconfidence level of an accuracy of each of the identified multipleoutputs, where each of the identified multiple outputs is created by aseparate upstream computational process in separate upstreamsubcomponents from the multiple upstream subcomponents. The computerhardware generates weighting values by assigning a weighting value toeach of the identified multiple inputs to the downstream subcomponent,where the weighting value describes a criticality level of each of theidentified multiple inputs when executing the downstream computationalprocess in the downstream subcomponent. The computer hardware utilizesthe determined accuracy values and the weighting values to dynamicallyadjust which of the identified multiple inputs are used by thedownstream subcomponent in an effort to generate an output from thedownstream subcomponent meets a predefined trustworthiness level formaking a first type of prediction, where a trustworthiness of the outputfrom the downstream subcomponent is based on the determined accuracyvalue of each of the identified multiple outputs and the weighting valueof each of the identified multiple inputs to the downstreamsubcomponent. The computer hardware determines that no variations ofexecution of one or more functions used by the downstream subcomponentever produce an output that meets the predefined trustworthiness levelfor making the first type of prediction. The computer hardware, inresponse to determining that no variations of execution of the one ormore functions used by the downstream subcomponent ever produce theoutput that meets the predefined trustworthiness level for making thefirst type of prediction, executes a new downstream computationalprocess that produces a different second type of prediction than thatproduced by the downstream subcomponent.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts an exemplary system and network which may be used toimplement the present invention;

FIG. 2 illustrates detail of a complex stream computer system depictedin FIG. 1; and

FIG. 3 is a high level flow chart of one or more exemplary steps takenby a processor or other computer hardware to prevent a cascading failurein a complex stream computer system.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of the presentinvention may be embodied as a system, method or computer programproduct. Accordingly, aspects of the present invention may take the formof an entirely hardware embodiment, an entirely software embodiment(including firmware, resident software, micro-code, etc.) or anembodiment combining software and hardware aspects that may allgenerally be referred to herein as a “circuit,” “module” or “system.”Furthermore, aspects of the present invention may take the form of acomputer program product embodied in one or more computer readablemedium(s) having computer readable program code embodied thereon.

Any combination of one or more computer readable medium(s) may beutilized. The computer readable medium may be a computer readable signalmedium or a computer readable storage medium. A computer readablestorage medium may be, for example, but not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus, or device, or any suitable combination of the foregoing. Morespecific examples (a non-exhaustive list) of the computer readablestorage medium would include the following: an electrical connectionhaving one or more wires, a portable computer diskette, a hard disk, arandom access memory (RAM), a read-only memory (ROM), an erasableprogrammable read-only memory (EPROM or Flash memory), an optical fiber,a portable compact disc read-only memory (CD-ROM), an optical storagedevice, a magnetic storage device, or any suitable combination of theforegoing. In the context of this document, a computer readable storagemedium may be any tangible medium that can contain, or store a programfor use by or in connection with an instruction execution system,apparatus, or device.

A computer readable signal medium may include a propagated data signalwith computer readable program code embodied therein, for example, inbaseband or as part of a carrier wave. Such a propagated signal may takeany of a variety of forms, including, but not limited to,electro-magnetic, optical, or any suitable combination thereof. Acomputer readable signal medium may be any computer readable medium thatis not a computer readable storage medium and that can communicate,propagate, or transport a program for use by or in connection with aninstruction execution system, apparatus, or device.

Program code embodied on a computer readable medium may be transmittedusing any appropriate medium, including, but not limited to, wireless,wireline, optical fiber cable, RF, etc., or any suitable combination ofthe foregoing.

Computer program code for carrying out operations for aspects of thepresent invention may be written in any combination of one or moreprogramming languages, including an object oriented programming languagesuch as Java, Smalltalk, C++ or the like and conventional proceduralprogramming languages, such as the “C” programming language or similarprogramming languages. The program code may execute entirely on theuser's computer, partly on the user's computer, as a stand-alonesoftware package, partly on the user's computer and partly on a remotecomputer or entirely on the remote computer or server. In the latterscenario, the remote computer may be connected to the user's computerthrough any type of network, including a local area network (LAN) or awide area network (WAN), or the connection may be made to an externalcomputer (for example, through the Internet using an Internet ServiceProvider).

Aspects of the present invention are described below with reference toflowchart illustrations and/or block diagrams of methods, apparatus(systems) and computer program products according to embodiments of theinvention. It will be understood that each block of the flowchartillustrations and/or block diagrams, and combinations of blocks in theflowchart illustrations and/or block diagrams, can be implemented bycomputer program instructions. These computer program instructions maybe provided to a processor of a general purpose computer, specialpurpose computer, or other programmable data processing apparatus toproduce a machine, such that the instructions, which execute via theprocessor of the computer or other programmable data processingapparatus, create means for implementing the functions/acts specified inthe flowchart and/or block diagram block or blocks.

These computer program instructions may also be stored in a computerreadable medium that can direct a computer, other programmable dataprocessing apparatus, or other devices to function in a particularmanner, such that the instructions stored in the computer readablemedium produce an article of manufacture including instructions whichimplement the function/act specified in the flowchart and/or blockdiagram block or blocks.

The computer program instructions may also be loaded onto a computer,other programmable data processing apparatus, or other devices to causea series of operational steps to be performed on the computer, otherprogrammable apparatus or other devices to produce a computerimplemented process such that the instructions which execute on thecomputer or other programmable apparatus provide processes forimplementing the functions/acts specified in the flowchart and/or blockdiagram block or blocks.

As noted herein, a complex stream computer utilizes software andhardware components that interact with one another, such that adownstream component is reliant on an output from an upstream componentin the complex stream computer. Thus, such systems are notoriouslydifficult to debug. That is, if the output of the entire stream computerfails, (i.e., if the output is an error code, is nonsense, is outside ofan acceptable range, etc.), the upstream cause within the complex streamcomputer is difficult to identify by simply backtracking. The presentinvention presents a novel approach to identifying root causes in suchcascade processes.

With reference now to the figures, and in particular to FIG. 1, there isdepicted a block diagram of an exemplary system and network that may beutilized by and/or in the implementation of the present invention. Notethat some or all of the exemplary architecture, including both depictedhardware and software, shown for and within computer 102 may be utilizedby software deploying server 150 and/or complex stream computer system156.

Exemplary computer 102 includes a processor 104 that is coupled to asystem bus 106. Processor 104 may utilize one or more processors, eachof which has one or more processor cores. A video adapter 108, whichdrives/supports a display 110, is also coupled to system bus 106. Systembus 106 is coupled via a bus bridge 112 to an input/output (I/O) bus114. An I/O interface 116 is coupled to I/O bus 114. I/O interface 116affords communication with various I/O devices, including a keyboard118, a mouse 120, a media tray 122 (which may include storage devicessuch as CD-ROM drives, multi-media interfaces, etc.), a printer 124, andexternal USB port(s) 126. While the format of the ports connected to I/Ointerface 116 may be any known to those skilled in the art of computerarchitecture, in one embodiment some or all of these ports are universalserial bus (USB) ports.

As depicted, computer 102 is able to communicate with a softwaredeploying server 150, as well as complex stream computer system 156,using a network interface 130. Network interface 130 is a hardwarenetwork interface, such as a network interface card (NIC), etc. Network128 may be an external network such as the Internet, or an internalnetwork such as an Ethernet or a virtual private network (VPN).

A hard drive interface 132 is also coupled to system bus 106. Hard driveinterface 132 interfaces with a hard drive 134. In one embodiment, harddrive 134 populates a system memory 136, which is also coupled to systembus 106. System memory is defined as a lowest level of volatile memoryin computer 102. This volatile memory includes additional higher levelsof volatile memory (not shown), including, but not limited to, cachememory, registers and buffers. Data that populates system memory 136includes computer 102's operating system (OS) 138 and applicationprograms 144.

OS 138 includes a shell 140, for providing transparent user access toresources such as application programs 144. Generally, shell 140 is aprogram that provides an interpreter and an interface between the userand the operating system. More specifically, shell 140 executes commandsthat are entered into a command line user interface or from a file.Thus, shell 140, also called a command processor, is generally thehighest level of the operating system software hierarchy and serves as acommand interpreter. The shell provides a system prompt, interpretscommands entered by keyboard, mouse, or other user input media, andsends the interpreted command(s) to the appropriate lower levels of theoperating system (e.g., a kernel 142) for processing. Note that whileshell 140 is a text-based, line-oriented user interface, the presentinvention will equally well support other user interface modes, such asgraphical, voice, gestural, etc.

As depicted, OS 138 also includes kernel 142, which includes lowerlevels of functionality for OS 138, including providing essentialservices required by other parts of OS 138 and application programs 144,including memory management, process and task management, diskmanagement, and mouse and keyboard management.

Application programs 144 include a renderer, shown in exemplary manneras a browser 146. Browser 146 includes program modules and instructionsenabling a world wide web (WWW) client (i.e., computer 102) to send andreceive network messages to the Internet using hypertext transferprotocol (HTTP) messaging, thus enabling communication with softwaredeploying server 150 and other computer systems.

Application programs 144 in computer 102's system memory (as well assoftware deploying server 150's system memory) also include a cascadeprocessing control logic (CPCL) 148. CPCL 148 includes code forimplementing the processes described below, including those described inFIGS. 2-3. In one embodiment, computer 102 is able to download CPCL 148from software deploying server 150, including in an on-demand basis,wherein the code in CPCL 148 is not downloaded until needed forexecution. Note further that, in one embodiment of the presentinvention, software deploying server 150 performs all of the functionsassociated with the present invention (including execution of CPCL 148),thus freeing computer 102 from having to use its own internal computingresources to execute CPCL 148.

Complex stream computer system 156 comprises upstream subcomponents 152and downstream subcomponent(s) 154. The upstream subcomponents 152execute upstream computational processes that produce outputs, which aresubsequently used as inputs to downstream computational processes thatare executed in the downstream subcomponent(s) 154. In one embodiment,the upstream subcomponents 152 and downstream subcomponent(s) 154 areeach individual, separate hardware entities (e.g., each subcomponent isa separate processor). In another embodiment, upstream subcomponents 152and downstream subcomponent(s) 154 are software entities that areexecuted within a same computer hardware system (or within differentcomputer hardware systems). FIG. 2 provides additional detail of complexstream computer system 156. Note that, in one embodiment, the complexstream computer system 156 is actually part of computer 102, such thatthe complex stream computer system is internal to and self-monitored bycomputer 102.

Note that the hardware elements depicted in computer 102 are notintended to be exhaustive, but rather are representative to highlightessential components required by the present invention. For instance,computer 102 may include alternate memory storage devices such asmagnetic cassettes, digital versatile disks (DVDs), Bernoullicartridges, and the like. These and other variations are intended to bewithin the spirit and scope of the present invention.

With reference now to FIG. 2, details are shown of complex streamcomputer system 156 from FIG. 1. Complex stream computer system 156comprises multiple upstream subcomponents 202 a-n (where “n” is aninteger). Each of the multiple upstream subcomponents 202 a-n utilizesinputs (not shown) to execute upstream processes (e.g., computer programcode) to generate an output. For example, upstream subcomponent 202 agenerates an output a, upstream subcomponent 202 b generates an outputb, and upstream subcomponent 202 n generates an output n. These outputsare utilized as inputs to one or more of the downstream computationalprocesses (e.g., elements 206, 208, 210, 212) in the downstreamsubcomponent 204.

For example, assume that X represents a prediction of whether a certaincrop will be profitable or not, and/or the extent of the profit or lossfrom the crop (i.e., X=a crop profitability prediction). Also, assumethat crop profitability prediction X must meet a predefinedtrustworthiness level. For example, this predefined trustworthinesslevel may be a 95% confidence level that the prediction of whether thecrop will be profitable or not will be accurate within some predefinedrange. In one embodiment, this confidence level is historical (i.e., howaccurate the prediction has been in the past), based on 1) how reliable,accurate, and/or specific (i.e., falling within a predefined range) theoutputs from the upstream subcomponents were, and 2) how critical eachof the inputs were to a downstream computational process that wasexecuting within the downstream subcomponent 204.

Thus, in this example, assume that input a is a weather prediction(e.g., precipitation amount, temperatures, etc.) for where and when thecrop will be grown. Assume further that input b is a prediction of whatinterest rates (that the farmer will have to pay when financingequipment, buying seeds, etc.) will be during a predefined time period(e.g., during the planting/growing season). Finally, assume that input nis a crop demand prediction, which predicts how high the demand will befor the crop at harvest time. By inputting all of these factors intocomputational process 206 (using functions f, g, and h), cropprofitability prediction X is generated. In one embodiment, the presentinvention takes the process further. In this embodiment, a determinationis made as to whether X meets the predefined trustworthiness leveldescribed herein. In order to make this determination, 1) the quality(“accuracy values”) of the inputs is determined; and 2) the criticality(“weighting value”) of the input is determined.

With regard to the “accuracy values” of the inputs, each upstreamcomputational process is examined. First, the quality of the source ofinputs to these upstream computational processes is examined. Forexample, if the inputs to the upstream computational process are fromknown and trusted sources, then the output from that computationalprocess is deemed to be more accurate (i.e., has a higher confidencelevel of accuracy) than an output that is the result of inputs fromunknown, little used, and/or untrusted sources. Similarly, the upstreamcomputational process itself is evaluated. For example, if a particularupstream computational process has a history of producing highlyaccurate and reliable weather predictions, then the output from thatparticular upstream computational process will be deemed to be moreaccurate than the output of another upstream computational process thathas a poor history for accurately predicting the weather.

With regard to the “weighting value” of the input, certain inputs to thedownstream computational process are more significant/critical thanother inputs. For example, assume that the crop profitability predictionX produced by downstream computational process 206 does not meet therequisite predefined trustworthiness level, due to the fact that input bis too inaccurate. However, by using input a and input n in a differentdownstream computational process 208 (which uses functions f′ and h′instead of functions f and h, which are found in downstreamcomputational process 206), a crop profitability prediction X that meetsthe requisite predefined trustworthiness level is generated. That is, inresponse to downstream computational process 206 failing to generate acrop profitability prediction X that meets the requisite predefinedtrustworthiness level, due to the poor quality of input b, downstreamcomputational process 208 is executed, with the resulting cropprofitability prediction X that does meet the requisite predefinedtrustworthiness level.

In one embodiment, no variations of execution of one or more of thefunctions f(a), g(b), and/or h(n) (using the inputs a, b, n) everproduce a crop profitability prediction X that meets the requisitepredefined trustworthiness level. In this embodiment, downstreamcomputational process 210 is executed. Note that while downstreamcomputational process 210 uses the same functions f, g, and/or h asdownstream computational process 206, downstream computational process210 produces a different prediction Y. That is, while execution of thefunctions f(a)+g(b)+h(n) is unable to produce a reliable cropprofitability prediction X, these same functions (or alternatively,other functions—not shown), using inputs a, b, n, are able to produce acrop yield prediction Y (e.g., how much crop will be produced, withoutpredicting whether or not the crop will be profitable), which meets somerequisite predefined trustworthiness level.

In another embodiment, again no variations of execution of one or moreof the functions f(a), g(b), and/or h(n) (using the inputs a, b, n) everproduce a crop profitability prediction X that meets the requisitepredefined trustworthiness level. In this embodiment, alternatedownstream computational process 212 is executed. Note that whiledownstream computational process 210 uses the same functions f, g,and/or h as downstream computational process 206, downstreamcomputational process 210 uses input a′ (from upstream subcomponent 214,which executes a different upstream computational process and/or usesdifferent inputs than upstream subcomponent 202 a) instead of input a(from upstream subcomponent 202 a). By changing the input to function ffrom a to a′, a reliable crop profitability prediction X, which meetsthe requisite predefined trustworthiness level, is produced.

Note that crop prediction is but one example of downstream computationalprocesses that can utilize the methodology described herein. Forexample, assume that a user desires to diagnose a disease in a patient.In this example, assume that input a is a first lab result analysis.This first lab result analysis may be a simple yes/no lab result.However, the lab may have a good reputation or a bad reputation foraccuracy, and thus the quality (“accuracy values”) of lab results fromthat lab may vary. Similarly, the first lab result analysis may be ahuman and/or mechanical analysis of a sample (e.g., an X-ray report, aDNA analysis, a microscopic examination of a blood/stool sample, etc.).As such, the quality of the first lab result analysis is dependent onthe quality of the persons/equipment performing the analysis.

Continuing with the disease diagnosis example, input b may be a secondlab result analysis, which also has its own accuracy value. Input n maybe a patient history analysis, which is the result of data mining of apatient's medical chart, etc. Again, the quality of these analysesdepends on the skill level of the persons performing the analysis, thequality of the inputs used by the respective upstream computationalprocesses, and/or the quality of the hardware/software used in theanalyses. As with the crop prediction described above, if the diseasediagnosis X does not meet a predefined trustworthiness level (e.g.,using a downstream computational process 206), then another downstreamcomputational process (e.g., downstream computational process 208) maybe executed; another diagnosis Y (i.e., determining that a patient hasdisease “y” instead of disease “x”) may be generated (e.g., usingdownstream computational process 210); and/or another input (e.g., a′from another lab) may be used to generate the originally desired diseasediagnosis X.

With reference now to FIG. 3, a high level flow chart of one or moreexemplary steps taken by a processor or other computer hardware toprevent a cascading failure (i.e., a cascading failure that results inan untrustworthy output from the complex stream computer system) ispresented. After initiator block 302, a processor receives a first setof binary data that identifies multiple subcomponents in a complexstream computer system (block 304). These identified multiplesubcomponents comprise both multiple upstream subcomponents (e.g.,upstream subcomponents 202 a-n shown in FIG. 2) and at least onedownstream subcomponent (e.g., downstream subcomponent 204 shown in FIG.2). As described in block 306, the processor receives a second set ofbinary data that identifies multiple outputs (e.g., a, b, n shown inFIG. 2) generated by the multiple upstream subcomponents.

As described in block 308, the processor receives a third set of binarydata that identifies multiple inputs to the downstream subcomponent.These identified multiple inputs to the downstream subcomponent are theidentified multiple outputs generated by the multiple upstreamsubcomponents, and the identified multiple inputs are inputs to adownstream computational process (e.g., one of elements 206, 208, 210,212 depicted in FIG. 2) that is executed by the downstream subcomponent.

As described in block 310, computer hardware (e.g., computer 102 and/ordownstream subcomponent(s) 154 shown in FIG. 1) generate accuracyvalues, for each of the outputs from the upstream subcomponents, byassigning an accuracy value to each of the identified multiple outputs.The accuracy value describes a confidence level of an accuracy of eachof the identified multiple outputs. As described herein, each of theidentified multiple outputs are created by a separate upstreamcomputational process in separate upstream subcomponents from themultiple upstream subcomponents.

As described in block 312, computer hardware (e.g., computer 102 and/ordownstream subcomponent(s) 154 shown in FIG. 1) generates weightingvalues by assigning a weighting value to each of the identified multipleinputs to the downstream subcomponent. As described herein, theweighting value describes a criticality level of each of the identifiedmultiple inputs when executing the downstream computational process inthe downstream subcomponent. For example, the input b was deemed to benon-critical in FIG. 2, since a valid result X could be generated byusing the downstream computational process 208 instead of downstreamcomputational process 206.

As described in block 314, computer hardware (e.g., computer 102 and/ordownstream subcomponent(s) 154 shown in FIG. 1) then utilizes theaccuracy values and the weighting values to dynamically adjust which ofthe identified multiple inputs are input to the downstream subcomponentuntil an output from the downstream subcomponent meets a predefinedtrustworthiness level. As described in FIG. 2, this dynamic adjustmentmay change which inputs are used by a same downstream computationalprocess (e.g., element 206 or 212 in FIG. 2), and/or the dynamicadjustment may change which algorithm (e.g., element 206 or 208 or 210in FIG. 2) is used. That is, in one embodiment, in response to theaccuracy values failing to cause the output of the downstreamcomputational process to meet the predefined trustworthiness level, thecomputer hardware replaces the downstream computational process in thedownstream subcomponent with an alternate downstream computationalprocess. The downstream subcomponent then reutilizes the accuracy valuesand the weighting values to dynamically adjust inputs to the alternatedownstream computation process until an output from the downstreamsubcomponent (e.g., using the alternate downstream subcomponent process)meets the predefined trustworthiness level. For example, inputs toalternate downstream computational process 212 shown in FIG. 2 may bedynamically adjusted by using input a′ instead of input a with functionf in the alternate computational process 212.

The process ends at terminator block 316.

The flowchart and block diagrams in the figures illustrate thearchitecture, functionality, and operation of possible implementationsof systems, methods and computer program products according to variousembodiments of the present disclosure. In this regard, each block in theflowchart or block diagrams may represent a module, segment, or portionof code, which comprises one or more executable instructions forimplementing the specified logical function(s). It should also be notedthat, in some alternative implementations, the functions noted in theblock may occur out of the order noted in the figures. For example, twoblocks shown in succession may, in fact, be executed substantiallyconcurrently, or the blocks may sometimes be executed in the reverseorder, depending upon the functionality involved. It will also be notedthat each block of the block diagrams and/or flowchart illustration, andcombinations of blocks in the block diagrams and/or flowchartillustration, can be implemented by special purpose hardware-basedsystems that perform the specified functions or acts, or combinations ofspecial purpose hardware and computer instructions.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the invention. Asused herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of various embodiments of the present invention has beenpresented for purposes of illustration and description, but is notintended to be exhaustive or limited to the invention in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art without departing from the scope and spiritof the invention. The embodiment was chosen and described in order tobest explain the principles of the invention and the practicalapplication, and to enable others of ordinary skill in the art tounderstand the invention for various embodiments with variousmodifications as are suited to the particular use contemplated.

Note further that any methods described in the present disclosure may beimplemented through the use of a VHDL (VHSIC Hardware DescriptionLanguage) program and a VHDL chip. VHDL is an exemplary design-entrylanguage for Field Programmable Gate Arrays (FPGAs), ApplicationSpecific Integrated Circuits (ASICs), and other similar electronicdevices. Thus, any software-implemented method described herein may beemulated by a hardware-based VHDL program, which is then applied to aVHDL chip, such as a FPGA.

Having thus described embodiments of the invention of the presentapplication in detail and by reference to illustrative embodimentsthereof, it will be apparent that modifications and variations arepossible without departing from the scope of the invention defined inthe appended claims.

What is claimed is:
 1. A computer hardware-implemented method ofpreventing a cascading failure in a complex stream computer system,wherein a cascading failure results in an untrustworthy output from thecomplex stream computer system, and wherein the computerhardware-implemented method comprises: receiving a first set of binarydata that identifies multiple subcomponents in a complex stream computersystem, wherein the identified multiple subcomponents comprise multipleupstream subcomponents and a downstream subcomponent, wherein themultiple upstream subcomponents execute upstream computationalprocesses, wherein the multiple upstream subcomponents reside within afirst computer hardware system, and wherein the downstream subcomponentresides within a second computer hardware system; receiving a second setof binary data that identifies multiple outputs generated by themultiple upstream subcomponents; receiving a third set of binary datathat identifies multiple inputs to the downstream subcomponent, whereinthe identified multiple inputs to the downstream subcomponent are theidentified multiple outputs generated by the multiple upstreamsubcomponents, and wherein the identified multiple inputs are inputs toa downstream computational process that is executed by the downstreamsubcomponent; examining, by computer hardware, each of the upstreamcomputational processes to determine an accuracy of each of theidentified multiple outputs based upon: a source of inputs to each ofthe upstream computational processes; and a history of each of theupstream computational processes for producing predictions that exceed apredetermined level of accuracy; generating, by computer hardware,accuracy values by assigning a determined accuracy value to each of theidentified multiple outputs, wherein the determined accuracy valuedescribes a confidence level of an accuracy of each of the identifiedmultiple outputs, and wherein each of the identified multiple outputs iscreated by a separate upstream computational process in separateupstream subcomponents from the multiple upstream subcomponents;generating, by the computer hardware, weighting values by assigning aweighting value to each of the identified multiple inputs to thedownstream subcomponent, wherein the weighting value describes acriticality level of each of the identified multiple inputs whenexecuting the downstream computational process in the downstreamsubcomponent; utilizing, by the computer hardware, the determinedaccuracy values and the weighting values to dynamically adjust which ofthe identified multiple inputs are used by the downstream subcomponentin an effort to generate an output from the downstream subcomponent thatmeets a predefined trustworthiness level for making a first type ofprediction, wherein a trustworthiness of the output from the downstreamsubcomponent is based on the determined accuracy value of each of theidentified multiple outputs and the weighting value of each of theidentified multiple inputs to the downstream subcomponent; determining,by the computer hardware, that no variations of execution of one or morefunctions used by the downstream subcomponent ever produce an outputthat meets the predefined trustworthiness level for making the firsttype of prediction; and in response to determining that no variations ofexecution of the one or more functions used by the downstreamsubcomponent ever produce the output that meets the predefinedtrustworthiness level for making the first type of prediction,executing, by the computer hardware, a new downstream computationalprocess that produces a different second type of prediction than thatproduced by the downstream subcomponent.
 2. The computerhardware-implemented method of claim 1, wherein the identified multiplesubcomponents of the complex stream computer system are hardwaresubcomponents.
 3. The computer hardware-implemented method of claim 2,further comprising: in response to the accuracy values and the outputfrom the downstream subcomponent failing to meet the predefinedtrustworthiness level, the computer hardware replacing the downstreamcomputational process in the downstream subcomponent with an alternatedownstream computational process; and reutilizing, by the downstreamsubcomponent, the accuracy values and the weighting values todynamically adjust inputs to the alternate downstream computationalprocess until execution of the alternate downstream computationalprocess results in an output that meets the predefined trustworthinesslevel.
 4. The computer hardware-implemented method of claim 2, furthercomprising: determining, by the computer hardware, that one of theidentified multiple outputs is a failing output that fails to meet theaccuracy values; determining, by the computer hardware, that executingan alternate downstream computational process without the failing outputresults in an output from the downstream subcomponent meeting thepredefined trustworthiness level; and executing, by the downstreamsubcomponent, the alternate downstream computational process without thefailing output.
 5. The computer hardware-implemented method of claim 1,wherein the identified multiple subcomponents of the complex streamcomputer system are software subcomponents.
 6. The computerhardware-implemented method of claim 1, further comprising: receiving,by the downstream subcomponent, a weather prediction as a first input,wherein the first input is generated by a first upstream subcomponentfrom the multiple upstream subcomponents; receiving, by the downstreamsubcomponent, an interest rate prediction as a second input, wherein thesecond input is generated by a second upstream subcomponent from themultiple upstream subcomponents; receiving, by the downstreamsubcomponent, a crop demand prediction as a third input, wherein thethird input is generated by a third upstream subcomponent from themultiple upstream subcomponents; and generating, by the downstreamsubcomponent, a crop profitability prediction for a crop based on theweather prediction, the interest rate prediction, and the crop demandprediction, wherein the crop profitability prediction meets thepredefined trustworthiness level.
 7. The computer hardware-implementedmethod of claim 1, further comprising: receiving, by the downstreamsubcomponent, a first lab test analysis as a first input, wherein thefirst input is generated by a first upstream subcomponent from themultiple upstream subcomponents; receiving, by the downstreamsubcomponent, a second lab test analysis as a second input, wherein thesecond input is generated by a second upstream subcomponent from themultiple upstream subcomponents; receiving, by the downstreamsubcomponent, a patient history analysis as a third input, wherein thethird input is generated by a third upstream subcomponent from themultiple upstream subcomponents; and generating, by the downstreamsubcomponent, a disease diagnosis based on the first lab test analysis,the second lab test analysis, and the patient history analysis, whereinthe disease diagnosis meets the predefined trustworthiness level.
 8. Acomputer program product for preventing a cascading failure in a complexstream computer system, wherein a cascading failure results in anuntrustworthy output from the complex stream computer system, andwherein the computer program product comprises: a non-transitorycomputer readable storage medium; first program instructions to identifymultiple subcomponents in a complex stream computer system, wherein theidentified multiple subcomponents comprise multiple upstreamsubcomponents and a downstream subcomponent, and wherein the multipleupstream subcomponents execute upstream computational processes, whereinthe multiple upstream subcomponents reside within a first computerhardware system, and wherein the downstream subcomponent resides withina second computer hardware system; second program instructions toidentify multiple outputs generated by the multiple upstreamsubcomponents; third program instructions to identify multiple inputs tothe downstream subcomponent, wherein the identified multiple inputs tothe downstream subcomponent are the identified multiple outputsgenerated by the multiple upstream subcomponents, and wherein theidentified multiple inputs are inputs to a downstream computationalprocess that is executed by the downstream subcomponent; fourth programinstructions to examine each of the upstream computational processes todetermine an accuracy of each of the identified multiple outputs basedupon: a source of inputs to each of the upstream computationalprocesses; and a history of each of the upstream computational processesfor producing predictions that exceed a predetermined level of accuracy;fifth program instructions to generate accuracy values by assigning anaccuracy value to each of the identified multiple outputs, wherein theaccuracy value describes a confidence level of an accuracy of each ofthe identified multiple outputs, and wherein each of the identifiedmultiple outputs is created by a separate upstream computational processin separate upstream subcomponents from the multiple upstreamsubcomponents; sixth program instructions to generate weighting valuesby assigning a weighting value to each of the identified multiple inputsto the downstream subcomponent, wherein the weighting value describes acriticality level of each of the identified multiple inputs whenexecuting the downstream computational process in the downstreamsubcomponent; seventh program instructions to utilize the accuracyvalues and the weighting values to dynamically adjust which of theidentified multiple inputs are used by the downstream subcomponent in aneffort to generate an output from the downstream subcomponent that meetsa predefined trustworthiness level for making a first type ofprediction, wherein a trustworthiness of the output from the downstreamsubcomponent is based on the accuracy value of each of the identifiedmultiple outputs and the weighting value of each of the identifiedmultiple inputs to the downstream subcomponent; eighth programinstructions to determine that no variations of execution of one or morefunctions used by the downstream subcomponent ever produce an outputthat meets the predefined trustworthiness level for making the firsttype of prediction; and ninth program instructions to, in response todetermining that no variations of execution of the one or more functionsused by the downstream subcomponent ever produce the output that meetsthe predefined trustworthiness level for making the first type ofprediction, execute a new downstream computational process that producesa different second type of prediction than that produced by thedownstream subcomponent; and wherein the first, second, third, fourth,fifth, sixth, seventh, eighth, and ninth program instructions are storedon the non-transitory computer readable storage medium.
 9. The computerprogram product of claim 8, wherein the identified multiplesubcomponents of the complex stream computer system are hardwaresubcomponents.
 10. The computer program product of claim 9, furthercomprising: tenth program instructions to, in response to the accuracyvalues and the output from the downstream subcomponent failing to meetthe predefined trustworthiness level, replace the downstreamcomputational process in the downstream subcomponent with an alternatedownstream computational process; and eleventh program instructions toreutilize the accuracy values and the weighting values to dynamicallyadjust inputs to the alternate downstream computational process untilexecution of the alternate downstream computational process results inan output that meets the predefined trustworthiness level; and whereinthe tenth and eleventh program instructions are stored on thenon-transitory computer readable storage medium.
 11. The computerprogram product of claim 9, further comprising: tenth programinstructions to determine that one of the identified multiple outputs isa failing output that fails to meet the accuracy values; eleventhprogram instructions to determine that executing an alternate downstreamcomputational process without the failing output results in an outputfrom the downstream subcomponent meeting the predefined trustworthinesslevel; and twelfth program instructions to execute the alternatedownstream computational process without the failing output; and whereinthe tenth, eleventh, and twelfth program instructions are stored on thenon-transitory computer readable storage medium.
 12. The computerprogram product of claim 8, wherein the identified multiplesubcomponents of the complex stream computer system are softwaresubcomponents.
 13. The computer program product of claim 8, furthercomprising: tenth program instructions to receive a weather predictionas a first input, wherein the first input is generated by a firstupstream subcomponent from the multiple upstream subcomponents; eleventhprogram instructions to receive an interest rate prediction as a secondinput, wherein the second input is generated by a second upstreamsubcomponent from the multiple upstream subcomponents; twelfth programinstructions to receive a crop demand prediction as a third input,wherein the third input is generated by a third upstream subcomponentfrom the multiple upstream subcomponents; and thirteenth programinstructions to generate a crop profitability prediction for a cropbased on the weather prediction, the interest rate prediction, and thecrop demand prediction, wherein the crop profitability prediction meetsthe predefined trustworthiness level; and wherein the tenth, eleventh,twelfth, and thirteenth program instructions are stored on thenon-transitory computer readable storage medium.
 14. The computerprogram product of claim 8, further comprising: tenth programinstructions to receive a first lab test analysis as a first input,wherein the first input is generated by a first upstream subcomponentfrom the multiple upstream subcomponents; eleventh program instructionsto receive a second lab test analysis as a second input, wherein thesecond input is generated by a second upstream subcomponent from themultiple upstream subcomponents; twelfth program instructions to receivea patient history analysis as a third input, wherein the third input isgenerated by a third upstream subcomponent from the multiple upstreamsubcomponents; and thirteenth program instructions to generate a diseasediagnosis based on the first lab test analysis, the second lab testanalysis, and the patient history analysis, wherein the diseasediagnosis meets the predefined trustworthiness level; and wherein thetenth, eleventh, twelfth, and thirteenth program instructions are storedon the non-transitory computer readable storage medium.
 15. A systemcomprising: a hardware processor, a computer readable memory, and anon-transitory computer readable storage medium; first programinstructions to identify multiple subcomponents in a complex streamcomputer system, wherein the identified multiple subcomponents comprisemultiple upstream subcomponents and a downstream subcomponent, andwherein the multiple upstream subcomponents execute upstreamcomputational processes, wherein the multiple upstream subcomponentsreside within a first computer hardware system, and wherein thedownstream subcomponent resides within a second computer hardwaresystem; second program instructions to identify multiple outputsgenerated by the multiple upstream subcomponents; third programinstructions to identify multiple inputs to the downstream subcomponent,wherein the identified multiple inputs to the downstream subcomponentare the identified multiple outputs generated by the multiple upstreamsubcomponents, and wherein the identified multiple inputs are inputs toa downstream computational process that is executed by the downstreamsubcomponent; fourth program instructions to examine each of theupstream computational processes to determine an accuracy of each of theidentified multiple outputs based upon: a source of inputs to each ofthe upstream computational processes; and a history of each of theupstream computational processes for producing predictions that exceed apredetermined level of accuracy; fifth program instructions to generateaccuracy values by assigning an accuracy value to each of the identifiedmultiple outputs, wherein the accuracy value describes a confidencelevel of an accuracy of each of the identified multiple outputs, andwherein each of the identified multiple outputs is created by a separateupstream computational process in separate upstream subcomponents fromthe multiple upstream subcomponents; sixth program instructions togenerate weighting values by assigning a weighting value to each of theidentified multiple inputs to the downstream subcomponent, wherein theweighting value describes a criticality level of each of the identifiedmultiple inputs when executing the downstream computational process inthe downstream subcomponent; seventh program instructions to utilize theaccuracy values and the weighting values to dynamically adjust which ofthe identified multiple inputs are used by the downstream subcomponentin an effort to generate an output from the downstream subcomponent thatmeets a predefined trustworthiness level for making a first type ofprediction, wherein a trustworthiness of the output from the downstreamsubcomponent is based on the accuracy value of each of the identifiedmultiple outputs and the weighting value of each of the identifiedmultiple inputs to the downstream subcomponent; eighth programinstructions to determine that no variations of execution of one or morefunctions used by the downstream subcomponent ever produce an outputthat meets the predefined trustworthiness level for making the firsttype of prediction; and ninth program instructions to, in response todetermining that no variations of execution of the one or more functionsused by the downstream subcomponent ever produce the output that meetsthe predefined trustworthiness level for making the first type ofprediction, execute a new downstream computational process that producesa different second type of prediction than that produced by thedownstream subcomponent; and wherein the first, second, third, fourth,fifth, sixth, seventh, eighth, and ninth program instructions are storedon the non-transitory computer readable storage medium for execution bythe hardware processor via the computer readable memory.
 16. The systemof claim 15, wherein the identified multiple subcomponents of thecomplex stream computer system are hardware subcomponents.
 17. Thesystem of claim 16, further comprising: tenth program instructions to,in response to the accuracy values and the output from the downstreamsubcomponent failing to meet the predefined trustworthiness level,replace the downstream computational process in the downstreamsubcomponent with an alternate downstream computational process; andeleventh program instructions to reutilize the accuracy values and theweighting values to dynamically adjust inputs to the alternatedownstream computational process until execution of the alternatedownstream computational process results in an output that meets thepredefined trustworthiness level; and wherein the tenth and eleventhprogram instructions are stored on the non-transitory computer readablestorage medium for execution by the hardware processor via the computerreadable memory.
 18. The system of claim 16, further comprising: tenthprogram instructions to determine that one of the identified multipleoutputs is a failing output that fails to meet the accuracy values;eleventh program instructions to determine that executing an alternatedownstream computational process without the failing output results inan output from the downstream subcomponent meeting the predefinedtrustworthiness level; and twelfth program instructions to execute thealternate downstream computational process without the failing output;and wherein the tenth, eleventh, and twelfth program instructions arestored on the non-transitory computer readable storage medium forexecution by the hardware processor via the computer readable memory.19. The system of claim 15, further comprising: tenth programinstructions to receive a weather prediction as a first input, whereinthe first input is generated by a first upstream subcomponent from themultiple upstream subcomponents; eleventh program instructions toreceive an interest rate prediction as a second input, wherein thesecond input is generated by a second upstream subcomponent from themultiple upstream subcomponents; twelfth program instructions to receivea crop demand prediction as a third input, wherein the third input isgenerated by a third upstream subcomponent from the multiple upstreamsubcomponents; and thirteenth program instructions to generate a cropprofitability prediction for a crop based on the weather prediction, theinterest rate prediction, and the crop demand prediction, wherein thecrop profitability prediction meets the predefined trustworthinesslevel; and wherein the tenth, eleventh, twelfth, and thirteenth programinstructions are stored on the non-transitory computer readable storagemedium for execution by the hardware processor via the computer readablememory.
 20. The system of claim 15, further comprising: tenth programinstructions to receive a first lab test analysis as a first input,wherein the first input is generated by a first upstream subcomponentfrom the multiple upstream subcomponents; eleventh program instructionsto receive a second lab test analysis as a second input, wherein thesecond input is generated by a second upstream subcomponent from themultiple upstream subcomponents; twelfth program instructions to receivea patient history analysis as a third input, wherein the third input isgenerated by a third upstream subcomponent from the multiple upstreamsubcomponents; and thirteenth program instructions to generate a diseasediagnosis based on the first lab test analysis, the second lab testanalysis, and the patient history analysis, wherein the diseasediagnosis meets the predefined trustworthiness level; and wherein thetenth, eleventh, twelfth, and thirteenth program instructions are storedon the non-transitory computer readable storage medium for execution bythe hardware processor via the computer readable memory.